Electric vehicles or fuel cell vehicles, which are eco-friendly vehicles, include a low voltage battery in order to supply power required to start the vehicles and to supply power to electric field loads that operate at low voltage.
When the low voltage battery in a vehicle is a lithium battery, the battery must be prevented from being fully discharged due to its own characteristics. Therefore, if a state of charge of an auxiliary battery is lower than a certain voltage, electrical connection between the auxiliary battery and a vehicle system is interrupted by a relay. In order to restart the vehicle while the electrical connection is interrupted, the relay needs to be manually turned on to make the electrical connection. When the auxiliary battery is excessively discharged, the vehicle needs to be jump-started using an external power supply.
Conventionally, when a discharged auxiliary battery is charged by connecting an external power supply thereto and power is supplied to a vehicle electric field load to jump-start a vehicle, the auxiliary battery may be damaged by overcurrent or overvoltage applied from the external power supply connected for the jump-start.
Further, since there is no an additional control process for stably controlling the electrical system of a vehicle in the conventional art, when jump-start is performed after a relay that sets the electrical connection of an auxiliary battery is turned off, the jump-start may not be performed or the vehicle may be shut down.
The foregoing is intended merely to aid in the understanding of the background of the present invention, and is not intended to mean that the present invention falls within the purview of the related art that is already known to those skilled in the art.